I enjoyed my stay at Theerachai's place. It was quiet, and the room had everything I needed. It was not as clean as other reviews had stated, but my guess is that there was different cleaning staff because I arrived New Year's Eve when many Thai people are on holiday. I assume it's normally very clean since so many have commented on that.
As others have stated, it's a bit far from the center of the city, so if you want to be there, better to choose another place. For me, this location was great. There are plenty of places to eat nearby, and a couple of fairly large malls less than a mile away. The place itself is nice and quiet. It's also not too far from the airport.
Theerachai responded quickly to all messages. We had some problems with the airbnb app when I tried to add a day and he tried to approve it, but eventually we were able to just work that out ourselves, and I really appreciated his flexibility. I would definitely stay at this place again if I am in Bangkok.